1. Field of the Invention
This invention relates to systems and methods for cleaning articles, and more particularly to systems and methods for cleaning radioactively contaminated tools and the like.
2. Description of the Prior Art
Tools and other articles that are used in connection with radioactive materials become contaminated. Substantially all of the contamination is in particulate form, or dissolved in various films and/or emulsions, which are located on or near the surface of the tools. Consequently, contaminated tools may be decontaminated by the removal of the particulates and the films.
In the past, methods have been suggested for cleaning radioactively contaminated tools. One method is performed by enveloping the article to be cleaned in an atmosphere of vaporized solvent. The solvent condenses upon the surface of the tool and dissolves the soluble contaminant or envelopes the particulates. The solvent is then drained off in droplet form and the articles is dried. The vapor cleaning method is not entirely satisfactory, because it depends solely upon the solubility of the contaminant and/or its ability to drip away the particulates, and does not produce any washing action to dislodge the contaminants.
Another cleaning method of the prior art involves immersing the article in a bath of solvent, and then creating currents in the bath with pumps or ultrasonics. The immersion method is somewhat more effective than the vapor method, because it combines with the action of the solvent, some washing action. However, the immersion method is not entirely satisfactory.
An improvement over the foregoing methods is disclosed in U.S. patent application Ser. No. 080,474, filed Oct. 1, 1979, by Joseph A. Capella, et al, and now abandoned, which includes spraying the article with a solvent prior to immersion of the article in a solvent bath. The spraying action produces results that are superior to those of the immersion and vapor methods, but is still not entirely satisfactory. The primary shortcoming of the prior spraying system resides in the relatively low pressure of the spray produced therein. A low pressure spray is necessary in the prior system because the cleaning chamber of that system is closed, and the introduction of a high pressure spray of solvent therein would subject the chamber to excessive structural loads.
A further shortcoming of the prior spray system lies in the fact that the articles to be cleaned are placed upon a rack or screen within the chamber and sprayed by fixed nozzles. The prior spray system has no means for manipulating the article or the spray for more effective coverage.